The security settings give you the ability to control the lifetime of user sessions, and whether to
allow your Magento store to run in a frame. (This setting can prevent clickjacking.) In addition
you can add a secret key to URLs, and determine the case sensitivity of login credentials.
For security reasons Magento strongly recommends against running your store in a frame
To configure Admin security:
1. On the Admin menu, select System > Configuration.
2. In the panel on the left, under Advanced, select Admin.
3. Click to expand the Security section, and complete the settings as needed.
4. When complete, click the Save Config button.